1. Field of the Invention
The present invention relates to a dewaxing device, and more particularly to a chemical dewaxing device used in dewaxing process of the metal injection molding.
2. The Related Art
Metal injection molding is a metalworking process where finely-powdered metal is mixed with a measured amount of binder and wetting agent to comprise a feedstock capable of being handled by plastic processing equipment through a process known as injection mold forming. Subsequent conditioning operations are performed on the molded shape, where the wetting agent and the binder are removed from a green part of product and metal particles are coalesced into the desired state for the metal alloy. In detail, the wetting agent is removed by chemical solvent or sintering furnace to form pores in dewaxing process of the metal injection molding, and the binder is thermal-cracked into binder gas to go out through the pores in sintering process of the metal injection molding.
In order to effectively achieve the dewaxing process, it is a common way that the wetting agent is removed by the chemical solvent. In detail, the wetting agent can be removed by repeatedly rinsing the green part of product with the chemical solvent or keeping soaking the green part of product in the chemical solvent so as to dissolve the wetting agent out of the green part of product, wherein the chemical solvent can be n-hexane, n-butane, bromopropane, cleaning naphtha and so on. Because of increased awareness of environmental protection, the chemical solvent has gradually tended to use the bromopropane solvent which has recyclable characteristics.
In the dewaxing process, when the bromopropane solvent reaches saturation state, a recycling process is done. In detail, in the recycling process, the saturated solution needs to be heated to boiling to separate into bromopropane steam and high concentration of non-volatile liquid waste wax. Then utilize a condensing unit to condense the bromopropane steam into liquid so as to obtain pure bromopropane solvent again. The high concentration of non-volatile liquid waste wax is removed out. However, in the recycling process, the saturated solution needs to be heated to boiling and then be cooled so that will have a strong impact on use life of the bromopropane solvent. So, a dewaxing device having an improved recycling system for doing the recycling process is required.